Arsenic removal by natural and chemically modified water melon rind in aqueous solutions and groundwater

Muhammad Bilal Shakoor, Nabeel Khan Niazi, Irshad Bibi, Muhammad Shahid, Fakhra Sharif, Safdar Bashir, Sabry M. Shaheen, Hailong Wang, Daniel C.W. Tsang, Yong Sik Ok, Jörg Rinklebe

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)

Abstract

Contamination of groundwater with toxic arsenic (As) has become an emerging health and environmental problem around the world, which has seen significant attention amongst the scientists for development of new sorbents to remediate As-contaminated water. Here, we explored the arsenate (As(V)) and arsenite (As(III)) sorption to natural water melon rind (WMR), xanthated WMR and citric acid-modified WMR in aqueous solutions, and determined potential of the most potent sorbent for As removal in groundwater. Xanthated WMR (X-WMR) showed relatively higher As(V) and As(III) removal than the citric acid modified WMR (CA-WMR) and natural WMR. The maximum As(III) (99%) and As(V) (98%) removal was obtained at pH 8.2 and 4.6, respectively, by X-WMR at 4 mg L−1 initial As(V) and As(III) concentrations and sorbent dose of 1 g L−1. Langmuir isotherm model best fitted (R2 of up to 0.96) the data both for As(III) and As(V) sorption to X-WMR. Sorption kinetics of As(V) and As(III) was well described (R2 of up to 0.99) by the pseudo second-order model on surface of the X-WMR. Thermodynamic investigations revealed that As(V) and As(III) sorption was endothermic and spontaneous. The FTIR spectroscopy depicted the presence of different surface function groups (–OH, –COOH, S-bearing (C=S, S=O and S–S)) which were involved in As(V) and As(III) sequestration on the sorbents examined here. Significantly, X-WMR showed (up to 49%) greater As(III) and As(V) sorption than that of natural WMR. Our results demonstrated that X-WMR efficiently removed 94%–100% (n = 16) of As from As-contaminated drinking well water which possessed detectable concentrations of some anions (e.g., SO4, CO3, HCO3). This study highlights that the X-WMR has potential to remove As, notably As(III), from solutions and drinking water, and might be utilized as a reactive medium for the treatment of As-contaminated water.

Original languageEnglish
Pages (from-to)1444-1455
Number of pages12
JournalScience of the Total Environment
Volume645
DOIs
Publication statusPublished - 2018 Dec 15

Keywords

  • Biowaste
  • Citric acid
  • Contamination
  • Groundwater
  • Human health
  • Sorption-desorption

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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